Search

Abstract Little is known about biological processes controlling inorganic phosphate (PO4) in groundwater ecosystems. Here we present analyses of groundwater samples from the Hetao Basin, China that show an increasing contribution of microbial cycling to groundwater PO4 from oxic to anoxic conditions along a flow path with phosphate-bound oxygen isotopes (δ18OPO4). Under oxic conditions, although 25–47% of the dissolved PO4 inherited the initial source signal of igneous apatite, groundwater δ18OPO4 reflected a pronounced impact of intracellular enzymatic cycling. Under anoxic conditions, dissolved PO4 carried a nearly exclusive equilibrium isotope signal, which was probably due to (i) release of PO4 with an equilibrium δ18OPO4 from Fe(III) oxides, as a result of Fe(III) reduction in the presence of Fe(III)- and sulfate-reducing bacteria; and/or (ii) cumulative microbial cycling of dissolved PO4 with increasing groundwater residence time. Our study highlights that PO4 in groundwater is tightly microbially cycled under a wide range of redox conditions and microbial cycling contributes to the release of PO4 in groundwater.

Abstract Remote sensing technology has the potential to enhance the lake’s large-scale and long-term dynamic monitoring capabilities significantly. High-quality in-situ datasets are essential for improving the accuracy and reliability of remote sensing retrieval of lake ecosystems. This dataset provides satellite-ground synchronized in-situ data on water multi-parameters for typical lakes in China spanning the period between 2020 and 2023. It includes quality-checked water optical parameters (remote sensing reflectance (Rrs), chlorophyll-a (Chl-a), total suspended matter (TSM) and Secchi disk depth (SDD)), and water surface temperature (WST) data. It encompasses 586 sampling points across 18 lakes. The dataset exhibits two significant highlights: Firstly, synchronous observations from multiple satellites are coordinated during the data collection effectively supporting the retrieval and validation of water remote sensing products. Secondly, it encompasses diverse data types, collecting synchronous measurements of Rrs and various parameters. This dataset will continuously update, substantially enhancing regional and global lake monitoring capabilities through satellite remote sensing data.

Objective To investigate the expression levels of platelet microparticles(PMPs) in patients with diabetic nephropathy (DN) and their relationship with renal injury. Methods Thirty DN patients, 30 T2DM patients without DN and 30 healthy controls were enrolled. Flow cytometry was used to detect the quantity and phenotype of PMPs, and ELISA was used to measure the levels of plasma renin, angiotensin Ⅱ (angiotoninⅡ, AngⅡ), vascular endothelial growth factor (vascular endothelial growth factor, VEGF) and transforming growth factor-β1(transforming growth factor-β1, TGF-β1). Kidney function was determined by blood biochemistry. Results The quantity of PMPs in the DN group was (1 564±346) particles/μL, which was significantly higher than that in the non-DN group (1 246±312) particles/μL and the control group (1 223±299) particles/μL (P

A strategy for the synthesis of α-carboline derivatives from indole-3-carboxaldehydes and 3-aminocyclohex-2-enones under metal-free conditions has been developed. The combination use of phenyliodine (III) diacetate (PIDA) and benzoic acid could significantly facilitate the corresponding [3 ​+ ​3] annulation process. This newly developed strategy featured unextraordinary chemoselectivity, good functional group tolerance and the preservation of the carbonyl group of the ketone substrates, which offers the possibility for further transformation of the products.

An in-depth exploration of fractional vegetation coverage (FVC) changes and driving mechanisms in the Yangtze River Delta (YRD) is crucial for maintaining regional ecological health and achieving sustainable development. We therefore calculate FVC in the YRD from 2012 to 2021 based on MODIS NDVI data, and analyze its spatiotemporal evolution. Multiple regression residual analysis and geographic detector model were used along with various auxiliary data to further explore its driving mechanisms in a hierarchical manner. Finally, the Hurst index was used to forecast future trends in FVC. The results show that: 1) Significant changes in FVC occurred around 2016, rapidly declining at a rate of 8.9×10-3a-1 from 2012 to 2016, followed by fluctuating growth at a rate of 5.2×10-3a-1 thereafter. 2) Although the overall development of FVC in the YRD tends toward stability, the fluctuation was pronounced in the Taihu Lake Basin. Improvement areas were mainly concentrated on both sides of the Yangtze River in the central part of the YRD and in the southern mountainous region. Degraded areas were concentrated in cities north of the Huai River. 3) Dynamic changes in FVC were primarily driven by a combination of climate and human activities, whereas spatial heterogeneity was mainly driven by factors such as elevation, slope, and landform type. The improvement in the explanatory power of anthropogenic factors for spatial heterogeneity when combined with natural factors was significant.

Herein, in situ water reflectance and TSM data obtained from several experiments on the Nanyi Lake from 2018 to 2022 and the Sentinel-3 Ocean and Land Colour Instrument (OLCI) satellite synchronization data were used to compare four atmospheric correction methods (FLAASH, 6S, ACOLITE, and C2RCC) and construct an empirical model for TSM inversion in the Nanyi Lake to analyze the spatial and temporal changes in the water quality in the Nanyi Lake from 2018 to 2023. On the Sentinel-3 OLCI data, the C2RCC algorithm showed the highest accuracy and overall performance stability (RMSE: 0.0014–0.0051 Sr−1, MAPE: 18.44%–68.47%, and BIAS: from −3.68% to 23.63%). The highest correlation was observed between the three-band ratio (B9 + B18)/B10 and the in situ TSM; the TSM inversion model constructed based on this inversion factor showed the best accuracy for the Nanyi Lake (R2: 0.76, RMSE: 5.01 mg/L, and MAPE: 28.46%). The spatial and temporal changes in TSM in the Nanyi Lake exhibited significant regularity. Specifically, the TSM was higher in 2018–2019, significantly decreased in 2020, and stabilized in 2021–2023. Owing to the effects of human activities, precipitation, and illumination, seasonal variation in the TSM in the Nanyi Lake was detected, with TSM decreasing in the following order: summer > autumn > spring > winter. Concerning spatial variations, high TSM was observed in the northwest, northeast, and southeast of the Nanyi Lake reclamation area and its surrounding lake area. River confluence and human activities affected the area, leading to significant fluctuations in TSM in 2018–2023.

The on-orbit radiometric calibration of spaceborne sensors is the foundation of quantitative remote sensing, and the calibration accuracy directly affects the quality of quantitative remote sensing products. The wide swath of the Chinese Ocean Color and Temperature Scanner (COCTS) onboard the HY-1C satellite makes it difficult to ignore errors caused by viewing angles during calibration. Thus, this article proposes a cross-calibration method based on the bottom-of-atmosphere (BOA) and top-of-atmosphere (TOA) spectral band adjustment factors (SBAFs). This method cross calibrates the COCTS sensor after correcting viewing geometry and radiometric differences. It is based on the Sentinel-3/ocean and land color instrument (OLCI) sensor. First, time-series data from the OLCI sensor were used to select calibration points in the Dunhuang area. Subsequently, the bidirectional reflectance distribution function (BRDF) for each corresponding spectral band of the OLCI sensor was constructed point by point. Next, the BOA and TOA SBAFs were calculated using the interpolated continuous spectra obtained from MOD09GA products. After correcting for the BRDF and SBAF, cross calibration between COCTS and OLCI was achieved. The results showed that the BOA SBAF model achieved higher precision calibration coefficients than the TOA SBAF model, with errors in each band below 5.76%. The proposed method can provide technical support for the cross calibration of wide-swath sensors.

Numerous spatiotemporal fusion (STF) methods have been developed to generate surface reflectance data with high spatial and temporal resolutions for dynamic monitoring. Although comparative studies have been conducted to assess various fusion methods, selecting the most suitable fusion method for acquiring long-term time series data remains a challenge. This article compared four representative STF methods based on the effect of 8 × n-day (n = 1, 2, …, 7) time scales between base and predicted data. These methods included the spatial and temporal adaptive reflectance fusion model (STARFM), flexible spatiotemporal data fusion (FSDAF), enhanced STARFM (ESTARFM), and sensor-bias driven spatio-temporal fusion model (BiaSTF). Accuracy was assessed using metrics such as the root-mean-square error, correlation coefficients, erreur relative globale adimensionnelle de synthèse, and spectral angle mapper. The results indicate that as the time scale increases, fusion accuracy decreases, with a significant drop observed at the 40-day mark. Compared with the 8-day scale, at the 40-day scale, the ERGAS of STARFM decreased by 20.66%, that of FSDAF by 17.00%, that of ESTARFM by 14.37%, and that of BiaSTF by 11.48%. Furthermore, STF methods based on two pairs of images demonstrate a notable advantage in capturing data from distant temporal phases. In regions with pronounced phenological changes and longer time scales, BiaSTF consistently exhibits the best fusion performance (ERGAS = 1.67), followed by ESTARFM (ERGAS = 1.85). These findings can aid in determining the most suitable STF methods and provide guidelines for the development of new methods.

The leaf area index (LAI) is one of the most important biophysical parameters of vegetation canopy, which is of great significance for estimating the growth and yield of tea trees. In the present era, tea plantations are becoming increasingly densely packed. However, there is a lack of accurate methods for measuring the LAI of densely planted tea trees. To explore LAI measurement and inversion methods applicable to densely planted tea trees, this study used tea trees in Langxi County as a case study. Using two commonly used measurement methods for densely and sparsely grown row crops and a measurement method for densely grown tea trees proposed based on practice, three sets of tea tree LAI were measured and compared with the true LAI value obtained using direct measurements. Using the set with the best performance to construct a regression model with vegetation indices, the LAI during the new shoot period of tea leaves is inverted. The results are summarized as follows. 1) According to the analysis of the direct measurements, the proposed measurement method for densely grown tea trees is the closest LAI values to the true values for densely planted tea trees in Langxi. 2) According to the fitting analysis, the common vegetation indices were significantly correlated with the LAI. The vegetation indices constructed with green, red edge, and shortwave infrared bands exhibited a higher correlation with the LAI than those constructed without these bands. Among them, EVIre exhibited the highest fitting accuracy.

Phase sensitive amplification is indispensable in promoting applications such as all-optical regenerators, quantum communications, all-optical analog-to-digital conversion, and long-distance communications. In this article, we proposed a vector dual-pump nondegenerate phase-sensitive amplification scheme based on ultra-silicon-rich nitride (Si7N3) waveguide, and theoretically verified its capability for all-optical regeneration of phase-encoded polarization-division multiplexing (PDM) signal without the need for complex polarization diversity structures. We achieved a gain extinction ratio (GER) of ∼37.5 dB by using a 3-mm-long Si7N3 waveguide with a high nonlinear coefficient (∼279 /W/m). Signal quality before and after regeneration is characterized by constellation diagram and error vector magnitude (EVM). The results show that the EVM of the degraded PDM differential phase-shift keying (DPSK) signals with two polarization states of 54% and 53.8%, can be improved to 13.6% and 13.6%, respectively, after regeneration, directly illustrating the remarkable phase noise suppression effect. The applicability of the scheme in PDM quadrature phase shift keying (QPSK) signals was further investigated. Similarly, the EVMs of the two polarization states of the deteriorated QPSK signals are optimized from 28.9% and 29.3% to 13.7% and 13.9%, respectively. The proposed scheme has promising applications in integrated all-optical processing systems and long-distance transmission of optical communications.

In the process of radiometric calibration, the corrections for bidirectional reflectance distribution functions (BRDFs) and spectral band adjustment factors (SBAFs) are crucial. Time-series MODIS images are commonly used to construct BRDFs by using the Ross–Li model in current research. However, the Ross–Li BRDF model is based on the linear relationship between the kernel models and is unable to take into account the nonlinear relationship between them. Furthermore, when using SBAF to account for spectral difference, a radiative transfer model is often used, but it requires many parameters to be set, which may introduce more errors and reduce the calibration accuracy. To address these issues, the random forest algorithm and a spectral interpolation convolution method using the Sentinel-2/multispectral instrument (MSI) are proposed in this study, in which the HuanJing-2A (HJ-2A)/charge-coupled device (CCD3) sensor is taken as an example, and the Dunhuang radiometric calibration site (DRCS) is used as a radiometric delivery platform. Firstly, a BRDF model by using the random forest algorithm of the DRCS is constructed using time-series MODIS images, which corrects the viewing geometry difference. Secondly, the BRDF correction coefficients, MSI reflectance, and relative spectral responses (RSRs) of CCD3 are used to correct the spectral differences. Finally, with the validation results, the maximum relative error between the calibration results of the proposed method and the official calibration coefficients (OCCs) published by the China Centre for Resources Satellite Data and Application (CRESDA) is 3.38%. When tested using the Baotou sandy site, the proposed method is better than the OCCs of the average relative errors calculated for all the bands except for the near-infrared (NIR) band, which has a larger error. Additionally, the effects of the light-matching method and the radiative transfer method, different approaches to constructing the BRDF model, using SBAF to account for spectral differences, different BRDF sources, as well as the imprecise viewing geometrical parameters, spectral interpolation method, and geometric positioning error, on the calibration results are analyzed. Results indicate that the cross-calibration coefficients obtained using the random forest algorithm and the proposed spectral interpolation method are more applicable to the CCD3; thus, they also account for the nonlinear relationships between the kernel models and reduce the error due to the radiative transfer model. The total uncertainty of the proposed method in all bands is less than 5.16%.

Introduction: The complex geometry of herringbone gear can lead to uneven surface strengthening, which affects the overall effect of treatment. Methods: A discrete element model (DEM) of shot peening for herringbone gears was developed, incorporating accurate gear surface parameters to study impact characteristics along the tooth profile. A finite element model (FEM) was created for small local units of the gear surface to calculate the residual stress and roughness. Results: There are a large number of low-velocity shots at the root of the gear, and the closer to the top of the gear, the higher the impact velocity of the shots, but the number of impacts also decreases. The surface roughness Sa near the root of the tooth is the smallest, the Sa at the pitch circle is the largest, and the Sa at the top of the tooth is intermediate. However, the residual stress levels at different positions of the tooth surface are not significantly different. Conclusion: The difference in tooth surface roughness of herringbone gear is the synergistic effect of shot impact velocity and shot frequency, but this synergistic effect has no significant effect on the stress after shot peening.

Abstract Background Alzheimer’s disease is a prevalent disease with a heavy global burden. Proteomics is the systematic study of proteins and peptides to provide comprehensive descriptions. Aiming to obtain a more accurate and convenient clinical diagnosis, researchers are working for better biomarkers. Urine is more convenient which could reflect the change of disease at an earlier stage. Thus, we conducted a cross-sectional study to investigate novel diagnostic panels. Methods We firstly enrolled participants from China-Japan Friendship Hospital from April 2022 to November 2022, collected urine samples, and conducted an LC–MS/MS analysis. In parallel, clinical data were collected, and clinical examinations were performed. After statistical and bioinformatics analyses, significant risk factors and differential urinary proteins were determined. We attempt to investigate diagnostic panels based on machine learning including LASSO and SVM. Results Fifty-seven AD patients, 43 MCI patients, and 62 CN subjects were enrolled. A total of 3366 proteins were identified, and 608 urine proteins were finally included in the analysis. There were 33 significantly differential proteins between the AD and CN groups and 15 significantly differential proteins between the MCI and CN groups. AD diagnostic panel included DDC, CTSC, EHD4, GSTA3, SLC44A4, GNS, GSTA1, ANXA4, PLD3, CTSH, HP, RPS3, CPVL, age, and APOE ε4 with an AUC of 0.9989 in the training test and 0.8824 in the test set while MCI diagnostic panel included TUBB, SUCLG2, PROCR, TCP1, ACE, FLOT2, EHD4, PROZ, C9, SERPINA3, age, and APOE ε4 with an AUC of 0.9985 in the training test and 0.8143 in the test set. Besides, diagnostic proteins were weakly correlated with cognitive functions. Conclusions In conclusion, the procedure is convenient, non-invasive, and useful for diagnosis, which could assist physicians in differentiating AD and MCI from CN.

Abstract The impacts of climate change-induced warming on our ecosystems can no longer be neglected, but our understanding of consequences for groundwater ecosystems in general and groundwater quality in particular is alarmingly incomplete. In this review, we therefore provide an overview of the current state of knowledge related to the impact of global warming on our precious groundwater resources. Groundwater warming in shallow aquifers is closely associated with increasing average land surface temperatures and has already reached + 1 K compared to pe-industrial times. Until the end of the twenty-first century, temperature increases in local groundwater of up to + 10 K are possible. Monitoring data, laboratory and field experiments all provide evidence that such temperature increases are sufficient to substantially modify groundwater quality through numerous and interlinked biogeochemical processes, which we have summarized in a conceptual overview. Warming impacts on groundwater are highly site-specific and spatially heterogeneous, which complicates their assessment and prediction. Locally, shallow unconfined and nutrient-rich floodplain aquifers are most susceptible to warming-induced changes. Importantly, processes affecting water quality are not only modified by a long-term rise in groundwater temperatures, but also in the short-term during weather extremes, which is of great relevance for riverbank filtration. At the regional scale, aquifers in cold regions impacted by permafrost thawing are especially vulnerable to warming. As the majority of temperature-sensitive processes affecting groundwater quality are not or only very slowly reversable, we pressingly require comprehensive mechanistic understanding before it is too late to develop suitable countermeasures and management strategies.

This paper proposes a synthetical multi-degree-of-freedom mathematical modelling for analyzing the dynamic characteristics of angular contact ball bearing with waviness subjected to the external load working conditions. The above multi-degree-of-freedom mathematical modelling is established based on nonlinear elastic Hertz contact theory and inner raceway control theory by employing improved Newton–Raphson iteration method; the validation of the established mathematical modelling is verified by comparing the presented results with the existing literature results. The above mathematical modelling has considered raceway waviness, ball waviness, bearing clearance, centrifugal force, gyroscopic moment, external loads, and rotating speed comprehensively. Firstly, the effects of waviness order and waviness amplitude on time-varying contact and stiffness characteristics of angular contact ball bearing are investigated systematically. Then, the influences of bearing clearance, rotating speed, axial force, radial force, and torque on the dynamic contact and stiffness characteristics of angular contact ball bearing with waviness are analyzed thoroughly. The main results show that the solution results of mathematical modelling have converged, respectively, when raceway waviness order increases to 25 and ball waviness order increases to 5; The variation tendencies of time-varying contact angle, contact force, and stiffness of angular contact ball bearing with waviness are aperiodic; The amplitudes of time-varying contact angle, contact force, and stiffness of angular contact ball bearing increase evidently with waviness amplitude increased; The bearing clearance has important influence on the contact angle and contact force of outer raceway and inner raceway, respectively; The effects of radial force and torque on contact and stiffness characteristics are consistent basically in the corresponding direction; The influences of axial force and rotating speed on the contact and stiffness characteristics are more remarkable compared with other factors. The investigations of contact and stiffness characteristics of angular contact ball bearing with waviness are helpful for the designation and manufacture of high precision angular contact ball bearing.

Cryptic species are commonly misidentified because of high morphological similarities to other species. One group of plants that may harbor large numbers of cryptic species is the quillworts (Isoëtes spp.), an ancient aquatic plant lineage. Although over 350 species of Isoëtes have been reported globally, only ten species have been recorded in China. The aim of this study is to better understand Isoëtes species diversity in China. For this purpose, we systematically explored the phylogeny and evolution of Isoëtes using complete chloroplast genome (plastome) data, spore morphology, chromosome number, genetic structure, and haplotypes of almost all Chinese Isoëtes populations. We identified three ploidy levels of Isoëtes in China—diploid (2n = 22), tetraploid (2n = 44), and hexaploid (2n = 66). We also found four megaspore and microspore ornamentation types in diploids, six in tetraploids, and three in hexaploids. Phylogenetic analyses confirmed that I. hypsophila as the ancestral group of the genus and revealed that Isoëtes diploids, tetraploids, and hexaploids do not form monophyletic clades. Most individual species possess a single genetic structure; however, several samples have conflicting positions on the phylogenetic tree based on SNPs and the tree based on plastome data. All 36 samples shared 22 haplotypes. Divergence time analysis showed that I. hypsophila diverged in the early Eocene (∼48.05 Ma), and most other Isoëtes species diverged 3–20 Ma. Additionally, different species of Isoëtes were found to inhabit different water systems and environments along the Yangtze River. These findings provide new insights into the relationships among Isoëtes species in China, where highly similar morphologic populations may harbor many cryptic species.

IntroductionAlzheimer’s disease is a prevalent disease with a heavy global burden and is suggested to be a metabolic disease in the brain in recent years. The metabolome is considered to be the most promising phenotype which reflects changes in genetic, transcript, and protein profiles as well as environmental effects. Aiming to obtain a comprehensive understanding and convenient diagnosis of MCI and AD from another perspective, researchers are working on AD metabolomics. Urine is more convenient which could reflect the change of disease at an earlier stage. Thus, we conducted a cross-sectional study to investigate novel diagnostic panels.MethodsWe first enrolled participants from China-Japan Friendship Hospital from April 2022 to November 2022, collected urine samples and conducted an LC–MS/MS analysis. In parallel, clinical data were collected and clinical examinations were performed. After statistical and bioinformatics analyzes, significant risk factors and differential urinary metabolites were determined. We attempt to investigate diagnostic panels based on machine learning including LASSO and SVM.ResultsFifty-seven AD patients, 43 MCI patients and 62 CN subjects were enrolled. A total of 2,140 metabolites were identified among which 125 significantly differed between the AD and CN groups, including 46 upregulated ones and 79 downregulated ones. In parallel, there were 93 significant differential metabolites between the MCI and CN groups, including 23 upregulated ones and 70 downregulated ones. AD diagnostic panel (30 metabolites+ age + APOE) achieved an AUC of 0.9575 in the test set while MCI diagnostic panel (45 metabolites+ age + APOE) achieved an AUC of 0.7333 in the test set. Atropine, S-Methyl-L-cysteine-S-oxide, D-Mannose 6-phosphate (M6P), Spiculisporic Acid, N-Acetyl-L-methionine, 13,14-dihydro-15-keto-tetranor Prostaglandin D2, Pyridoxal 5’-Phosphate (PLP) and 17(S)-HpDHA were considered valuable for both AD and MCI diagnosis and defined as hub metabolites. Besides, diagnostic metabolites were weakly correlated with cognitive functions.DiscussionIn conclusion, the procedure is convenient, non-invasive, and useful for diagnosis, which could assist physicians in differentiating AD and MCI from CN. Atropine, M6P and PLP were evidence-based hub metabolites in AD.

Caragana korshinskii is a deciduous shrub with large eco-economic value and strong tolerance to abiotic stresses. However, the shortage of reliable genetic transformation technology severely hinders its research on stress tolerance mechanisms and stress-resistant gene mining and application. In this study, the embryonic tip of the C. korshinskii seedling was used as the initiating explant to get regenerated plant through the direct organogenesis pathway, which significantly shortened the culture cycle and set the foundation for investigation of Agrobacterium-mediated genetic transformation. Our results suggest that the embryonic tip possesses robust meristem capacity and is an efficient method for transgenic breeding. This research provides a technical basis for asexual reproduction, molecular breeding, and gene function investigation in C. korshinskii by establishing, for the first time, an effective in vitro regeneration system and an Agrobacterium-mediated stable genetic transformation system utilizing the embryonic tip of C. korshinskii as explants.

Abstract Aim Non‐alcoholic fatty liver disease (NAFLD)‐related advanced liver fibrosis (Stage 3 or 4) was reported to be linked to worse prognosis in patients with heart failure with preserved ejection fraction (HFpEF). This study aims to assess the relationship between liver fibrosis scores and new‐onset atrial fibrillation (AF) incidence in patients with HFpEF in the Treatment of Preserved Cardiac Function Heart Failure with an Aldosterone Antagonist (TOPCAT) trial. Methods and results Baseline liver fibrosis levels, assessed by NAFLD fibrosis score (NFS) or Fibrosis‐4 index (FIB‐4), with AF incidence were expressed as hazard ratios (HRs) using the Cox proportional hazard model. The risk for advanced fibrosis was estimated to be 21.5% (447/2072) as assessed by FIB‐4 (>3.25) and 4.2% (88/2072) as assessed by NFS (>0.676) in HFpEF patients without baseline AF. After a median follow‐up of 3.11 years, 106 new‐onset AF cases occurred. In multivariate analysis, elevated NFS [NFS = −1.455–0.676: HR 2.44, 95% confidence interval (CI) 1.27–4.68; NFS > 0.676: HR 3.36, 95% CI 1.27–6.80; per 1 unit increase: HR 1.15, 95% CI 1.01–1.32], not FIB‐4 (FIB‐4 = 1.45–3.25: HR 1.02, 95% CI 0.67–1.55; FIB‐4 > 3.25: HR 1.69, 95% CI 0.76–3.79; per 1 unit increase: HR 1.13, 95% CI 0.93–1.37), was associated with increased AF incidence. The NFS (C‐index 0.662), not FIB‐4 (C‐index 0.531), had a moderate predictive ability in predicting incident AF. Conclusions Among patients with HFpEF, the risk of advanced liver fibrosis is associated with an increased incidence of new‐onset AF and may be a novel predictor for new‐onset AF. Additional studies are needed to confirm our results.

Abstract The considerable heat treatment induced runout value in the end face of the automobile main reducer gear is always dimensionally out of tolerance. It directly affects the dimensional accuracy, the grade of carburized and hardened gears, and the post-quenching manufacturing costs. In this study, three dimensional numerical models were developed to simulate the carburizing-quenching process of gear based on the multi-field coupling theory using DEFORM software. The results indicated that the ununiform cooling rate of the gear caused by the asymmetry of the web structure would result in the ununiform distribution of martensite, leading to the large runout value at the end face of the gear. Therefore, a novel method was proposed to minimize the heat treatment induced runout value. It was found that the heat treatment induced runout value could be effectively controlled by the addition of a compensation ring and the support of a rod structure. Further experiments showed that the average runout value of the gear end face before and after the proposed heat treatment method were about 0.023 mm and 0.059 mm respectively, which was in good agreement with the simulated results. The novel approach proposed in this study led to a reduction of the gear runout value by 70.0%‒76.9% compared to that of the original heat treatment process, which may serve as a practical and economical way to predict and minimize the heat treatment induced distortion in drive gear.

Abstract Background Aging is related with memory deterioration. However, some older adults demonstrate superior performance compared to age- and education-matched adults, who are referred to as superagers. To explore the neural mechanisms that mediate their unusually successful memory is important not only for the ameliorate the effects of aging in brain, but also for the prevention of neurodegenerative diseases, including Alzheimer’s disease. This case-control study is aimed to investigate the effects of volume and function of basal forebrain cholinergic neurons on the cognition of superagers. Methods The morphometric and resting-state functional MRI analysis, including 34 superagers and 48 typical older adults, were conducted. We compared the basal forebrain gray matter density and related resting-state functional connectivity (FC) in the two groups. To investigate the relationship of FC with cognition, we measure the correlation of significant altered FC and individual cognitive domain. Results No significant differences of gray matter density was observed between superagers and typical older adults. The superagers had stronger cortical FC of Ch1-3 with left putamen and insular cortex. The strength of FC positively correlated with global cognition, memory and executive function. Conclusions These findings demonstrated that the stronger FC of basal forebrain correlated with specific cognitive difference in global cognition and domains of memory and executive function in superagers.

Due to the high energy efficiency per bit and high sensitivity, Return-to-zero differential-phase-shift-keying (RZ-DPSK) is perfectly suitable for free-space laser communications. However, the conventional generation method of RZ-DPSK optical signal requires two modulators, which is costly, bulky, and heavy, significantly hindering the application of RZ-DPSK in size, weight, and power (SWaP)-constrained satellite platforms. In this paper, we propose and experimentally demonstrate a modulator-free variable multi-rate RZ-DPSK free-space optical (FSO) communication system based on chirp-managed laser (CML). Based on the proposed scheme, an FSO outfield experiment over 1 km has been successfully undertaken, achieving receiving sensitivities of −48.9 dBm and −45.6 dBm at 2.5 Gbps and 5 Gbps, with bit error rate (BER) of 1 × 10−3 without forward error correction (FEC), respectively. The performance of the proposed system is also investigated by studying the eye diagrams under two different test conditions of back-to-back transmission and 1-km free space transmission. In addition to the small size, lightweight and low cost, the proposed scheme shows great potential for a variety of FSO communication applications ranging from Cube-Star to larger satellite laser communication platforms.

Radiation-induced intestinal injury (RIII) restricts the therapeutic efficacy of radiotherapy in abdominal or pelvic malignancies. Also, intestinal injury is a major cause of death following exposure to high doses of radiation in nuclear accidents. No safe and effective prophylactics or therapeutics for RIII are currently available. Here, we reported that the apigenin, a natural dietary flavone, prolonged the survival in c57 mice after lethal irradiation. Apigenin pretreatment brought about accelerated restoration of crypt-villus structure, including enhanced regenerated crypts, more differentiated epithelium cells, and increased villus length. In addition, intestinal crypt cells in the apigenin-treated group exhibited more proliferation and less apoptosis. Furthermore, apigenin increased the expression of Nrf2 and its downstream target gene HO-1, and decreased oxidative stress after irradiation. In conclusion, our findings demonstrate the radioprotective efficacy of apigenin. Apigenin has the potential to be used as a radioprotectant in cancer therapy and nuclear accidents.

This study attempts to solve the problems such as low efficiency and relatively small range due to the constraints of device and monotony of vibration in ultrasonic assisted rolling of gears. A novel double-roller longitudinal torsional compound gear ultrasonic rolling system including a longitudinal torsional compound horn and its matching tool gear is proposed. Through the theoretically calculation method， the frequency equation of the horn is derived and the relevant design parameters are calculated. The longitudinal torsional compound vibration displacement and trajectory at the tooth surface are calculated by FEM with spiral grooves in the conical section and the assembled gear. The influences of different parameters of spiral groove such as number， depth， width and helical angle of the groove on torsional longitudinal compound vibration is analyzed by univariate method， FEM and an introduced parameter torsional longitudinal vibration ratio. The optimal parameter combination is obtained and the tool the gear is designed by using lightweight design method. The results show that the design of compound horn meets the requirements， and the effective longitudinal torsional compound vibration of the assembled gear is obtained. The longitudinal torsional compound vibration can be generated with spiral grooves in the conical section. The torsional vibration is mainly related to the number， depth， width and helical angle of the grooves. The double-roller gear longitudinal torsional compound ultrasonic rolling system is obtained by assembling with tool gear， it provides a technical support for the performance of the new gear longitudinal-torsional ultrasonic rolling device.

Background:Conflicting findings of the association between serum uric acid (SUA) and atrial fibrillation (AF) have been reported in both men and women. The sex-specific associations between SUA and the risk of AF are unclear, although hyperuricemia is independently associated with the risk of AF. We performed this meta-analysis to assess the sex-specific effect of SUA on the risk of AF.MethodsThe PubMed, EMBASE, and Cochrane Library databases were searched up to October 3, 2021, for studies that reported sex-specific associations of SUA levels with AF. Linear relationships were assessed by the generalized least squares trend estimation. This study was registered with PROSPERO (42020193013).ResultsTen eligible studies with 814,804 participants (415,779 men and 399,025 women) were identified. In the category analysis, high SUA was associated with an increased risk of AF in both men (OR: 1.42; 95% CI, 1.18–1.71, I2 = 34%) and women (OR: 2.02; 95% CI, 1.29–3.16, I2 = 70%). In the dose-response analysis, for each 60 μmol/L (1 mg/dL) increase in the SUA level, the risk of AF increased by 15% (OR: 1.15; 95% CI, 1.07–1.25, I2 = 74%) in men and 35% (OR: 1.35; 95% CI, 1.18–1.53, I2 = 73%) in women. There was a borderline difference in the impact of SUA on the risk of AF between men and women (P for interaction = 0.05). A significant linear relationship between SUA and the risk of AF was observed in men (P for non-linearity = 0.91) and women (P for non-linearity = 0.92).ConclusionsThis study suggested that there was a significant linear relationship between SUA and the risk of AF among men and women, with a higher risk estimate for women. Additional trials are required to assess the effect of reduced SUA therapy on AF incidence.Systematic Review Registrationhttps:www.crd.york.ac.uk/PROSPERO/, identifier: CRD 42020193013.

This paper presents a numerical study on stress-constrained shell-lattice infill structural optimisation. This problem is inherently challenging for several reasons: (i) different stress measures have to be used for the solid shell and the porous lattice infill, and the two types of stress constraints make the problem extremely complex to solve and (ii) involvement of the shell layer further complicates the optimisation problem modelling and its solution. To address these challenges, two stress constraints were formulated, i.e. a von Mises stress-based constraint for the solid shell layer and a Tsai-Hill yield criteria-based constraint for the porous lattice. Then, level set function is adopted to represent the shape of the shell layer and the constant-thickness shell layer is modelled based on the signed distance feature. Then, a comprehensive and accurate sensitivity result is derived to guide the concurrent structural shape and lattice density optimisation. A few numerical examples will be studied to prove the effectiveness of the developed algorithm. Some interesting phenomena have been observed, such as the soft narrow band at the shell-lattice interface to mitigate stress concentration.

Due to its high hardness and brittleness, sapphire is difficult to obtain a low grinding roughness. In this paper, the cerium oxide liquid is used to assist the grinding of sapphire with a diamond wheel with relatively big-size grains to obtain a low roughness. The effects of grain size, the crystal orientation of the sapphire, and the pH values of the cerium oxide liquid on the assisted grinding process have been analyzed. It is shown that with the proposed method, the roughness of 45 nm and subsurface damage of 141 nm are obtained, respectively. Compared with the grinding surfaces obtained without the assistant, the roughnesses and the subsurface damage of the assisted grinding surfaces are reduced by 60.8% and 84.5% when #600 wheel is used, respectively. Moreover, in the grinding experiments, the crystal orientation of the sapphire and the pH values of the cerium oxide liquid have little effect on the roughness of the grinding surface, while the grain size has a great impact. It is concluded that the improvement of the surface roughness by using the proposed method benefits from the combined action of the grinding of grains and the polishing of the cerium oxide liquid.

Flower color not only determines the quality and commercial value of ornamental plants, but it also plays a vital role in ecological processes such as pollinator attraction. This study aimed to investigate the relationship between flower color and the cellular physicochemical factors of Bletilla striata. The color space values of 21 samples were initially determined, followed by a selection of five samples with significant color differences for testing cell shape, total flavonoid content (ranging from 1.86 to 5.42 mg/g), total anthocyanin content (ranging from 0.52 to 292.62 (A530 − 0.25 ∗ A657)/g), cell pH (varying between 5.03 and 5.74), and metal ion content (including Al3+, Ca2+, Fe3+, K+, Mg2+, Na+, P5+, Zn2+, Mo6+, Cu2+, and Mn2+). The flowers of Bletilla were predominantly purple, pink, and yellow; and distributed in quadrants I, II, and IV on the a* and b* rectangular coordinate. The a* value was identified as the primary color indicator for this species. Total anthocyanin content and Zn2+ showed a significant positive correlation with a*, while Al3+, Ca2+, Fe3+, Mg2+, Na+, and Mn2+ demonstrated negative correlations. Cell shape, flavonoid content, and pH had nonsignificant correlations with a*. In conclusion, the total anthocyanin content and metal ions play crucial roles in determining the flower color of B. striata, which can have implications for pollinator attraction. Future research should focus on understanding the complex interactions between these factors to develop novel ornamental plant varieties with desirable flower colors and enhanced ecological functions.

Background: Epidemiological studies have shown that atrial fibrillation (AF) is a potential cardiovascular complication of coronavirus disease 2019 (COVID-19). We aimed to perform a systematic review and meta-analysis to clarify the prevalence and clinical impact of AF and new-onset AF in patients with COVID-19.Methods: PubMed, Embase, the Cochrane Library, and MedRxiv up to February 27, 2021, were searched to identify studies that reported the prevalence and clinical impact of AF and new-onset AF in patients with COVID-19. The study was registered with PROSPERO (CRD42021238423).Results: Nineteen eligible studies were included with a total of 21,653 hospitalized patients. The pooled prevalence of AF was 11% in patients with COVID-19. Older (≥60 years of age) patients with COVID-19 had a nearly 2.5-fold higher prevalence of AF than younger (

The precise three-dimensional measurement of fuel nozzles is of great significance to assess the manufacturing accuracy and improve the spray and atomization performance. This paper proposes an improved fast shape from focus (SFF) method for three-dimensional measurement of key features of fuel nozzles. In order to ensure the measurement accuracy and efficiency of the SFF, the dispersion of the measured points from a standard flat plane was used to select the optimal combination of the focus measure operator, window size and sampling step size. In addition, an approximate method for the focus measure interval is proposed to improve the measurement efficiency, which uses the peak region of the central pixel to replace the peak region of other pixels. The results show that the proposed method decreased the average computation time of the focus measure by 79.19% for the cone section and by 38.30% for the swirl slot. Compared with a reference laser scanning microscope, the measurement error in length is within 10 μm and the error in angle is within a maximum 0.15°.

RNA imaging is of great importance for understanding its complex spatiotemporal dynamics and cellular functions. Considerable effort has been devoted to the development of small-molecule fluorescent probes for RNA imaging. However, most of the reported studies have mainly focused on improving the photostability, permeability, long emission wavelength, and compatibility with live-cell imaging of RNA probes. Less attention has been paid to the selectivity and detection limit of this class of probes. Highly selective and sensitive RNA probes are still rarely available. In this study, a new set of styryl probes were designed and synthesized, with the aim of upgrading the detection limit and maintaining the selectivity of a lead probe QUID−1 for RNA. Among these newly synthesized compounds, QUID−2 was the most promising candidate. The limit of detection (LOD) value of QUID−2 for the RNA was up to 1.8 ng/mL in solution. This property was significantly improved in comparison with that of QUID−1. Further spectroscopy and cell imaging studies demonstrated the advantages of QUID−2 over a commercially available RNA staining probe, SYTO RNASelect, for highly selective and sensitive RNA imaging. In addition, QUID−2 exhibited excellent photostability and low cytotoxicity. Using QUID−2, the global dynamics of RNA were revealed in live cells. More importantly, QUID−2 was found to be potentially applicable for detecting RNA granules in live cells. Collectively, our work provides an ideal probe for RNA imaging. We anticipate that this powerful tool may create new opportunities to investigate the underlying roles of RNA and RNA granules in live cells.

ObjectiveEmerging evidence suggests that white matter (WM) disruption is associated with the incidence of subcortical vascular cognitive impairment (SVCI). However, our knowledge regarding this relationship in the early stage of SVCI is limited. We aimed to investigate the associations between WM disruptions and cognitive declines at the early stage of SVCI.MethodWe performed a case–control study, involving 22 cases and 19 controls. The cases were patients at the early stage of SVCI, which was defined as subcortical ischemic vascular disease with normal global cognitive measures (pre-SVCI). The controls were healthy people matched by age, sex, and education years. We assessed the differences in a battery of neuropsychological tests between the two groups, investigated the diffusion changes in 40 WM tracts among the participants via an atlas-based segmentation strategy, and compared the differences between the cases and controls by multiple linear regression analysis. We then evaluated the relationships between diffusion indices and cognitive assessment scores by Pearson’s correlation.ResultsThe pre-SVCI group exhibited significant differences in the Montreal cognitive assessment (MoCA), Rey–Osterrieth Complex Figure (R-O)-copy, and Trail Making Test (TMT)-B test compared with the controls. Compared with the controls, some long associative and projective bundles, such as the right anterior corona radiata (ACR), the right inferior fronto-occipital fasciculus (IFOF), and the left external capsule (EC), were extensively damaged in cases after Bonferroni correction (p < 0.05/40). Damages to specific fibers, such as the right ACR, IFOF, and posterior thalamic radiation (PTR), exhibited significant correlations with declines in MoCA, R-O delay, and the Mini-Mental State Examination (MMSE), respectively, after Bonferroni correction (p < 0.05/14).ConclusionLong WM tracts, especially those in the right hemisphere, were extensively damaged in the pre-SVCI patients and correlated with declines in executive functions and spatial processing. Patients of pre-SVCI are likely at an ultra-early stage of SVCI, and there is a very high risk of this condition becoming SVCI.

People with subjective cognitive decline (SCD) and amnestic mild cognitive impairment (aMCI) are both at high risk for Alzheimer’s disease (AD). Behaviorally, both SCD and aMCI have subjective reports of cognitive decline, but the latter suffers a more severe objective cognitive impairment than the former. However, it remains unclear how the brain develops from SCD to aMCI. In the current study, we aimed to investigate the topological characteristics of the white matter (WM) network that can successfully identify individuals with SCD or aMCI from healthy control (HC) and to describe the relationship of pathological changes between these two stages. To this end, three groups were recruited, including 22 SCD, 22 aMCI, and 22 healthy control (HC) subjects. We constructed WM network for each subject and compared large-scale topological organization between groups at both network and nodal levels. At the network level, the combined network indexes had the best performance in discriminating aMCI from HC. However, no indexes at the network level can significantly identify SCD from HC. These results suggested that aMCI but not SCD was associated with anatomical impairments at the network level. At the nodal level, we found that the short-path length can best differentiate between aMCI and HC subjects, whereas the global efficiency has the best performance in differentiating between SCD and HC subjects, suggesting that both SCD and aMCI had significant functional integration alteration compared to HC subjects. These results converged on the idea that the neural degeneration from SCD to aMCI follows a gradual process, from abnormalities at the nodal level to those at both nodal and network levels.

Abstract Background Blood donor plasma samples were detected by the Ultrio Plus NAT system for HBV, HCV and HIV-1 in Shenzhen blood center, China. Reactive samples underwent further discriminatory testing of a single virus by the same methodology. A large number of cases of non-discriminated reactive (NDR) donors were found, leaving potential risk of transmitting HBV if not deferrals. This study identified those non-discriminated samples. Methods The NDR plasma samples from blood donation screening were detected and classified by additional molecular and serological tests. Molecular characterizations of DNA+ NDR were determined by sequencing analysis. Results A number of 259 (0.21%) NDR plasma samples from screening of 123,280 eligible blood donors were detected, which presented a higher rate (91.1%) of anti-HBc reactivity and nearly half (46.7%) of HBV DNA+ that classified as occult HBV infection (OBI). Most OBI strains were wild-type HBV, but some substitutions V168A, S174 N, V177A, Q129R/L/H, G145A/R in S region of genotype B (OBIB) and T47K/V/A, P49H/L, Q101R/H/K, S174 N, L175S, V177A, T118 M/R/K, G145R/A/K/E, R160K/N in S region of genotype C (OBIC) strains were identified in high frequency. Conclusion Nearly half of NDR blood samples were identified as OBI, in which a number of important mutations were detected. NDR donation might have potential risk for HBV transmission, but need to be further investigated.

Based on the material structure thermodynamics and heat treatment commercial simulation software， combined with the heat treatment process of the driven gear of the actual vehicle final reducer， the heat treatment deformation of gears of 20CrMoH and 8620H materials are researched. Taking the driven gear of the final reducer as the research object， the performance database of 20CrMoH and 8620H materials is established by JMATPRO software， and the numerical analysis model of the gear carburizing and pre-cooling quenching process is established. By using DEFORM software simulation，the of heat treatment deformation information of 20CrMoH and 8620H gears is obtained. The research shows that， the carbon content and hardness of the 8620H gear surface are less than 20CrMoH material，compared with 20CrMoH， the 8620H gear heat treatment deformation is smaller and more uniform.

This case-control study is aimed to investigate the correlation of altered functional connectivity (FC) in cerebellum with cognitive impairment in amnestic mild cognitive impairment (aMCI) and Alzheimer’s disease (AD). The morphometric and resting-state FC MRI analysis including 46 participants with AD, 32 with aMCI and 42 age-matched normal controls (NCs) were conducted. We compared the cerebellar gray matter volume and cerebellar FC with cerebral cortical regions among three groups. To investigate the relationship of cerebellar FC with cognition, we measure the correlation of significant altered FC and individual cognitive domain. No significant morphometric differences of cerebellum was observed across three groups. The patients with AD had weaker cerebral cortical FCs in bilateral Crus I and left VIIb compared to NCs, and in bilateral Crus I compared to patients with aMCI. For patients with aMCI, the weaker FC were found between right Crus I, left VIIb and cerebral cortical regions compared to NCs. The strength of left cerebellar FC positively correlated with specific cognitive subdomains, including memory, executive function, visuospatial function, and global cognition in AD and aMCI. These findings demonstrated the alteration of cerebellar FC with cerebral cortical regions, and the correlation of cerebellar FC and cognitive impairment in AD and aMCI.

Summary: Repetitive elements are abundantly distributed in mammalian genomes. Here, we reveal a striking association between repeat subtypes and gene function. SINE, L1, and low-complexity repeats demarcate distinct functional categories of genes and may dictate the time and level of gene expression by providing binding sites for different regulatory proteins. Importantly, imaging and sequencing analysis show that L1 repeats sequester a large set of genes with specialized functions in nucleolus- and lamina-associated inactive domains that are depleted of SINE repeats. In addition, L1 transcripts bind extensively to its DNA in embryonic stem cells (ESCs). Depletion of L1 RNA in ESCs leads to relocation of L1-enriched chromosomal segments from inactive domains to the nuclear interior and de-repression of L1-associated genes. These results demonstrate a role of L1 DNA and RNA in gene silencing and suggest a general theme of genomic repeats in orchestrating the function, regulation, and expression of their host genes. : Lu et al. report a striking association between genomic repeats and gene regulation and demonstrate a key role of L1 repeat RNA in sequestering L1-rich sequences and associated genes in inactive domains for silencing, revealing a general theme of repeat sequences in shaping gene regulatory networks within their host genome. Keywords: repetitive elements, L1, B1 or Alu, SINE, low-complexity repeats, gene function, regulation and expression, nucleolus and lamina-associated domains, L1 RNA, gene silencing

Accurate and updated aerosol optical properties (AOPs) are of vital importance to climatology and environment-related studies for assessing the radiative impact of natural and anthropogenic aerosols. We comprehensively studied the columnar AOP observations between January 2019 and July 2020 from a ground-based remote sensing instrument located at a rural site operated by Central China Comprehensive Experimental Sites in the center of the Yangtze River Delta (YRD) region. In order to further study the aerosol type, two threshold-based aerosol classification methods were used to investigate the potential categories of aerosol particles under different aerosol loadings. Based on AOP observation and classification results, the potential relationships between the above-mentioned results and meteorological factors (i.e., humidity) and long-range transportation processes were analyzed. According to the results, obvious variation in aerosol optical depth (AOD) during the daytime, as well as throughout the year, was revealed. Investigation into AOD, single-scattering albedo (SSA), and absorption aerosol optical depth (AAOD) revealed the dominance of fine-mode aerosols with low absorptivity. According to the results of the two aerosol classification methods, the dominant aerosol types were continental (accounting for 43.9%, method A) and non-absorbing aerosols (62.5%, method B). Longer term columnar AOP observations using remote sensing alongside other techniques in the rural areas in East China are still needed for accurate parameterization in the future.

In view of problem that traditional magnetic circuit calculation for motor cannot accurately calculate reactances of quadrature-axis and direct-axis of motor because reluctance of iron core is neglected, the paper used Maxwell software to make electromagnetic analysis for an interior permanent magnet synchronous motor. The analysis results show that it cannot consider saturation of magnetic circuit of direct-axis, but must consider saturation of magnetic circuit of quadrature-axis when calculating reactances of quadrature-axis and direct-axis. There is cross magnetic circuit in direct-axis and quadrature-axis, so influence of cross saturation of magnetic circuit on reactances cannot be neglected when calculating reactances of quadrature-axis and direct-axis.